Go4Expert - Can't seem to figure this error out

For a challenge, we have to code a script that can pull information from a web page and then use it to automate an action on that site. What I've chosen to try and do is code an IPB Forum Advertiser. The process is easy, but I can't seem to get it to work.

The Problem: so far I can't seem to get it to login and not sure what I'm doing wrong.

Code:

#!/usr/bin/perl

use LWP::UserAgent;

use HTTP::Cookies;

$host = @ARGV[0];

@badID = (1,2,3,4,5);

$arrSize = @badID;

$i = 2;



if (@ARGV < 1)

{

  print "\n\n [-] Specify a host";

  print "\n\n [!] Example: pm.pl http://www.sitename.com/path/\n\n";

  exit(0);

}

loginPrompt();

sub login($$)

{

  $browser = LWP::UserAgent->new(agent =>

        'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; T312461)' ,

  );

  $cookie_jar = HTTP::Cookies->new();

  $browser->cookie_jar($cookie_jar);



    $response = $browser->post( $host.'/index.php?act=Login&CODE=01',

       [ 'referer' => '',

         'UserName' =>$_[0],

         'PassWord'=>$_[1],

     'CookieDate' => '1',

     'Privacy' => '1',

         'submit'=>'Log me in' ]

       );

$content = $response->content;



if ($content =~ /<head>/gmi)

{print "\n[-] INCORRECT LOGIN\n"; loginPrompt()}

else{msgInfo()}

}

sub spam()

{

  for ($j = 0; $j <= $arrSize + 1; $j++)

  {

   if ($i > $uid){ print "\n\n



    * Spamming Completed\n"; exit(0) }



   if ($badID[$j] eq $i) { $i++; spam() }

  }



     sleep(15);



     $res = $browser->get("$host/index.php?act=Msg&CODE=4&MID=$i");

     $results = $res->content;

     if ($results =~ /name="post_key" value="([a-f0-9]{32})"(.*)/){$postkey = $1;}

     if ($results =~ /name="auth_key" value="([a-f0-9]{32})"(.*)/){$authkey = $2;}

     if ($results =~ /name="entered_name"(.*) value="(.*?)"(.*)/gmi){$name = $3;}



     $resp = $browser->post( "$host/index.php?act=msg",

        [ 'removeattachid'=> '0',

          'OID'=>'',

          'act'=>'Msg',

          'CODE'=>'04',

          'MODE'=>'01',

          'post_key'=> $postkey,

          'auth_key'=>$authkey,

      'entered_name'=>$name,

          'msg_title'=> $subj,

      'Post'=> $msg,

          'post'=>'Submit', Referer => $host ]

        );



    print "\n [!] Message Sent to: $name with SID $SID";



    if ($i > $uid){print "\n\n



    * Spamming Completed\n"; exit(0)}



    else{$i++;spam()}

}

sub loginPrompt()

{

  print "\nEnter your login name: ";

  chomp($id = <STDIN>);

  print "\nEnter your password: ";

  chomp($pass = <STDIN>);

  login($id, $pass);

}

sub msgInfo()

{

  print "\nEnter message subject: ";

  chomp($subj = <STDIN>);

  print "\nEnter your message: ";

  chomp($msg = <STDIN>);

  print "\nEnter highest uid: ";

  chomp($uid = <STDIN>);

  spam();

}